Temporal processing is an essential ability for successful listening in complex environments, yet there is a significant gap in knowledge regarding the development of this process in childhood. The objective of this project is to use electrophysiological and psychophysical techniques to identify factors responsible for immature temporal processing in children. The central hypothesis is that behavioral measures of temporal processing underestimate the fidelity of temporal information encoded in the peripheral auditory system of children ? information the central auditory system is unable to take full advantage of due to immaturity of higher-level auditory processing, including informational masking, or ?confusion effects?. This central hypothesis will be tested in two specific aims. AIM 1 uses neural indices of signal-in-noise detection to test the hypothesis that maturation of temporal processing occurs at different rates within the peripheral auditory system compared to within the central auditory system. AIM 2 uses psychoacoustical techniques to test the hypothesis that reducing the burden of higher-level auditory processing results in improved auditory temporal processing in children. The expected outcomes of this research project include clarification of the extent to which the developmental effects seen in behavioral estimates of non-simultaneous masking reflect a limitation in the fidelity of neural encoding and higher-level auditory processing. This research is significant because it will provide an objective gauge of maturational effects in temporal processing in children with normal hearing obtained from within the peripheral and central auditory systems. In addition, this research establishes the impact of non-sensory effects on children?s temporal processing in complex environments and assesses the applicability of psychophysical results to stimuli aligned more closely with real-world environments (i.e., speech). The proposed research training program is designed to foster acquisition of the technical skills and background knowledge in auditory temporal development that will form the bedrock of a research career using electrophysiological and psychoacoustical techniques to study pediatric auditory development to uncover the sources of deficits and delays observed for children with hearing loss compared to children with normal hearing.